From 6fe7de802014d0c967e3b839ccda7711b1028029 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rub=C3=A9n=20Norte?= <rubennorte@gmail.com>
Date: Mon, 14 Apr 2025 20:25:18 +0100
Subject: [PATCH] fix: Add DOCTYPE and XML preamble in exported SVG documents
 (#9386)

* Add DOCTYPE and XML preamble in exported SVG documents

* Update packages/excalidraw/data/index.ts

---------

Co-authored-by: David Luzar <5153846+dwelle@users.noreply.github.com>
---
 packages/common/src/constants.ts  | 3 +++
 packages/excalidraw/data/index.ts | 7 ++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/packages/common/src/constants.ts b/packages/common/src/constants.ts
index 7eb36d5d9..cd3bd7a15 100644
--- a/packages/common/src/constants.ts
+++ b/packages/common/src/constants.ts
@@ -319,6 +319,9 @@ export const DEFAULT_MAX_IMAGE_WIDTH_OR_HEIGHT = 1440;
 export const MAX_ALLOWED_FILE_BYTES = 4 * 1024 * 1024;
 
 export const SVG_NS = "http://www.w3.org/2000/svg";
+export const SVG_DOCUMENT_PREAMBLE = `<?xml version="1.0" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+`;
 
 export const ENCRYPTION_KEY_BITS = 128;
 
diff --git a/packages/excalidraw/data/index.ts b/packages/excalidraw/data/index.ts
index ac8147e85..93d5f5677 100644
--- a/packages/excalidraw/data/index.ts
+++ b/packages/excalidraw/data/index.ts
@@ -5,6 +5,7 @@ import {
   isFirefox,
   MIME_TYPES,
   cloneJSON,
+  SVG_DOCUMENT_PREAMBLE,
 } from "@excalidraw/common";
 
 import { getNonDeletedElements } from "@excalidraw/element";
@@ -134,7 +135,11 @@ export const exportCanvas = async (
     if (type === "svg") {
       return fileSave(
         svgPromise.then((svg) => {
-          return new Blob([svg.outerHTML], { type: MIME_TYPES.svg });
+          // adding SVG preamble so that older software parse the SVG file
+          // properly
+          return new Blob([SVG_DOCUMENT_PREAMBLE + svg.outerHTML], {
+            type: MIME_TYPES.svg,
+          });
         }),
         {
           description: "Export to SVG",